BITSAT2009ChemistryHaloalkanes and HaloarenesActual
Which of the following order is not correct?
Options
- AMeBr > Me ₂ CHBr > Me ₃ CBr > Et ₃ CBr ( S _ N 2 )
- BMe ₃ CBr > Me ₂ CHBr > Me ₂ CH.CH ₂ Br > MeCH ₂ CH ₂ CH ₂ Br . ( E ₂ )
- CPhCH ₂ Br > Ph CHBrMe > PhCBrMe ₂> PhCBrMePh ( S _ N 1 )
- DMeI > MeBr > MeCl > MeF ( S _ N 2 )
Correct answer
C. PhCH ₂ Br > Ph CHBrMe > PhCBrMe ₂> PhCBrMePh ( S _ N 1 )
Step-by-step solution
The more is the stability of intermediate carbonium ion, the more is the chance of S _ N 1 mechanism. The intermediates obtained will be Ph ⁺ C H ₂( i ), Ph C H - Me ( ii ) Ph C - Me ₂ ( . iii) , Ph C ⁺ MePh (iv) The stabilty is of the order iv > iii > ii > i